The cost effectiveness of pharmacological treatments for generalized anxiety disorder.

Background: Generalized anxiety disorder (GAD) is one of the most prevalent anxiety disorders, with important implications for patients and healthcare resources. However, few economic evaluations of pharmacological treatments for GAD have been published to date, and those available have assessed only a limited number of drugs.

Objective: To assess the cost effectiveness of pharmacological interventions for patients with GAD in the UK.

Methods: A decision-analytic model in the form of a decision tree was constructed to compare the costs and QALYs of six drugs used as first-line pharmacological treatments in people with GAD (duloxetine, escitalopram, paroxetine, pregabalin, sertraline and venlafaxine extended release [XL]) and 'no pharmacological treatment'. The analysis adopted the perspective of the NHS and Personal Social Services (PSS) in the UK. Efficacy data were derived from a systematic literature review of double-blind, randomized controlled trials and were synthesized using network meta-analytic techniques. Two network meta-analyses were undertaken to assess the comparative efficacy (expressed by response rates) and tolerability (expressed by rates of discontinuation due to intolerable side effects) of the six drugs and no treatment in the study population. Cost data were derived from published literature and national sources, supplemented by expert opinion. The price year was 2011. Probabilistic sensitivity analysis was conducted to evaluate the underlying uncertainty of the model input parameters.

Results: Sertraline was the best drug in limiting discontinuation due to side effects and the second best drug in achieving response in patients not discontinuing treatment due to side effects. It also resulted in the lowest costs and highest number of QALYs among all treatment options assessed. Its probability of being the most cost-effective drug reached 75 % at a willingness-to-pay threshold of £20,000 per extra QALY gained.

Conclusion: Sertraline appears to be the most cost-effective drug in the treatment of patients with GAD. However, this finding is based on limited evidence for sertraline (two published trials). Sertraline is not licensed for the treatment of GAD in the UK, but is commonly used by primary care practitioners for the treatment of depression and mixed depression and anxiety.